Renal conditions

Question 1

What is chronic kidney disease (CKD)?

Answer 1

abnormal kidney structure and/or function
common but frequently undetected
often coincides with other conditions (e.g. CVD, diabetes) which increase in severity as disease progresses
risk increases with age
can progress to end-stage kidney disease in a small percentage of people
usually asymptomatic but detectable with tests

Question 2

Moderate to severe CKD is associated with an increased risk of which significant adverse outcomes?

Answer 2

acute kidney injury
falls
frailty
mortality

Question 3

List some nephrotoxic drugs which require at least annual monitoring of GFR.

Answer 3

calcineurin inhibitors (e.g. cyclosporin, tacrolimus)
lithium
NSAIDs

Question 4

What risk factors require testing for CKD using eGFRcreatinine and ACR?

Answer 4

diabetes, hypertension, acute kidney injury
CVD (ischaemic heart disease, chronic heart failure, peripheral vascular disease, cerebral vascular disease)
structural renal tract disease, recurrent renal calculi, prostatic hypertrophy
multisystem diseases with potential kidney involvement (e.g. systemic lupus erythematosus)
family history of end-stage kidney disease (GFR category G5) or hereditary kidney disease
opportunistic detection of haematuria

Question 5

How should clinical laboratories report GFR values?

Answer 5

as a whole number if it is 90 ml/min/1.73 m2 or less, or as ‘greater than 90 ml/min/1.73 m2’

Question 6

What is a creatinine-based estimate of GFR?

Answer 6

whenever a request for serum creatinine measurement is made, clinical laboratories should report an estimate of glomerular filtration rate (eGFRcreatinine)

Question 7

What factors should be considered when interpreting eGFRcreatinine?

Answer 7

people with extremes of muscle mass (e.g. bodybuilders, amputees, muscle-wasting disorders)
reduced muscle mass will lead to overestimation and increased muscle mass will lead to underestimation of GFR
people are advised not to eat any meat in the 12 hrs before the blood test for eGFRcreatinine

Question 8

What is a cystatin C-based estimate of GFR?

Answer 8

whenever a request for serum cystatin C measurement is made, clinical laboratories should report an estimate of glomerular filtration rate (eGFRcystatinC)

Question 9

What factors should be considered when interpreting eGFRcystatinC?

Answer 9

people with uncontrolled thyroid disease

eGFRcystatinC values may be falsely elevated in people with hypothyroidism and reduced in people with hyperthyroidism

Question 10

When should a cystatin C-based estimate of GFR for the diagnosis of CKD be considered?

Answer 10

at initial diagnosis to confirm/rule out CKD in people with an eGFRcreatinine of 45-59 ml/min/1.73 m2, sustained for at least 90 days and no proteinuria albumin:creatinine ratio [ACR] less than 3 mg/mmol)

Question 11

Name the six GFR categories (ml/min/1.73 m2).

Answer 11

GI, G2, G3a, G3b, G4, G5

Question 12

G1 - description and range

Answer 12

≥90

normal and high

Question 13

G2 - description and range

Answer 13

60-89

mild reduction related to the normal range for a young adult

Question 14

G3a - description and range

Answer 14

45-59

mild-moderate reduction

Question 15

G3b - description and range

Answer 15

30-44

moderate-severe reduction

Question 16

G4 - description and range

Answer 16

15-29

severe reduction

Question 17

G5 - description and range

Answer 17

<15

kidney failure

Question 18

Name the three ACR categories (mg/mmol).

Answer 18

A1, A2, A3

Question 19

A1 - description and range

Answer 19

<3

normal to mildly increased

Question 20

A2 - description and range

Answer 20

3-30

moderately increased

Question 21

A3 - description and range

Answer 21

> 30

severely increased

Question 22

List three complications of CKD.

Answer 22

anaemia
hyperkalaemia
vitamin deficiency

Question 23

Why does CKD lead to anaemia?

Answer 23

reduced production of erythropoietin

Question 24

Why does CKD lead to hyperkalaemia?

Answer 24

reduced excretion of potassium

Question 25

Why does CKD lead to vitamin D deficiency?

Answer 25

reduced ability to convert vitamin D into an active hormone (calcitriol)
calcitriol helps to regulate calcium and phosphate levels

Question 26

List some examples whereby a patient with CKD should be referred to an appropriate specialist.

Answer 26

isolated but persistent haematuria and urological cancer is suspected
eGFR <30 mL/min/1.73 m2
suspected urinary tract obstruction

Question 27

What lifestyle advice should be given to patients with CKD?

Answer 27

to take exercise
to achieve a healthy weight
to stop smoking
(tailored to the patient’s ability)

Question 28

What dietary interventions should be given to patients with CKD?

Answer 28

advice about potassium, phosphate, calorie and salt intake appropriate to the severity of CKD
in late-stage CKD, achieving balanced levels of vitamins and minerals in the diet is difficult
dietary intervention through education, detailed dietary assessment and supervision is necessary to avoid malnutrition

Question 29

What pharmacological interventions may be given to patients with CKD?

Answer 29

anti-hypertensives and statins
tailored to the patient
aim for systolic BP <140 mmHg (target range 120–139 mmHg) and diastolic BP <90 mmHg
anticoagulants
monitoring for anaemia and vitamin D deficiency

Question 30

When is renal replacement failure (RRT) offered to patients with CKD?

Answer 30

GFR <15

kidney failure

Question 31

What other factors might be considered when deciding whether to commence RRT?

Answer 31

when the symptoms of uraemia impact on daily living
biochemical measures or uncontrollable fluid overload
eGFR of 5-7 ml/min/1.73 m2 if there are no symptoms
the decision to start dialysis is made by the patient (family/carers, if appropriate) and healthcare team
impact on biopsychosocial needs
demands on the patient and others in managing the condition

Question 32

What factors determine the type of dialysis a patient receives?

Answer 32

predicted quality of life
predicted life expectancy
the person’s preferences
other factors such as co-existing conditions

Question 33

A review of services in England found that over 90 days after starting RRT, what percentage of patients were on haemodialysis?

Answer 33

67%

Question 34

What percentage of patients were on peritoneal dialysis?

Answer 34

19%

Question 35

What percentage of patients were due to receive a renal transplant?

Answer 35

8%

Question 36

What percentage of patients had died or stopped treatment?

Answer 36

6%

Question 37

What is continuous ambulatory peritoneal dialysis (CAPD)?

Answer 37

performed at home
manual exchange
takes 30 mins completed 4 times daily (morning, lunchtime, dinner time, bedtime)

Question 38

What are the two types of CAPD?

Answer 38

automated peritoneal dialysis (APD) and external access catheter

Question 39

What is automated peritoneal dialysis (APD)?

Answer 39

this approach may require access via a catheter placed by an open surgical technique
would need to be created around 2 weeks before the start of dialysis
utilises a machine that performs the exchange overnight (8-10 hours)

Question 40

What is haemodialysis/haemofiltration/haemodiafiltration (HD/HF/HDF)?

Answer 40

given when PD is unsuitable due to the level of kidney dysfunction, patient choice, ability and understanding
offered in a hospital or satellite unit, or even the home
delivered via an arteriovenous fistula, which needs to be fitted around 6 months before the start of dialysis

Question 41

How does haemodialysis operate?

Answer 41

uses a partially permeable membrane
intermittent process (e.g. three short sessions per week)
fast flow rate using a pump enabling processing of large blood volumes
rapid clearance of low molecular weight solutes by diffusion, comparatively little loss of fluid
speed and clearance of solutes determined by molecular size, osmotic pull across the membrane, and flow rate

Question 42

How does haemofiltration operate?

Answer 42

uses a highly permeable membrane
slow flow rate of blood but a continuous, 24 hr process, therefore large volumes of fluid removed
solute removed by filtration
pump not needed if blood is supplied from an artery and returns to a vein, pump used if blood originates from a vein
larger pores in the membrane than in haemodialysis so clears comparatively more medium molecular weight solutes

Question 43

How does haemodiafiltration operate?

Answer 43

uses a permeable membrane that allows diffusion (various techniques to achieve this)
adopts elements of dialysis and filtration
the membrane allows diffusion and filtration
continuous process
blood is pumped if a venous-venous connection is made, not if there is an arterio-venous connection (less common)
the most effective at removing solutes

Question 44

List some complications of kidney failure and dialysis.

Answer 44

hypotension (a common side effect of haemodialysis)
hypertension
fluid overload 
muscle cramps
itching
sleep problems
anaemia
bone diseases